The present invention relates to a metalclad switchgear having at least one circuit breaker and equipment cooperating with each circuit breaker, and to a circuit interrupting device for housing the circuit breaker.
A metalclad switchgear of the type described above is already known. In a typical structure of the metalclad switchgear, the circuit breaker and the cooperating equipment are housed in a single closed box, and the position of the cooperating equipment in the closed box is determined by the position of the circuit breaker as main equipment. FIGS. 1 and 2 are schematic views showing typical structures of conventional three-phase metalclad switchgears. The three-phase metalclad switchgear in FIG. 2 has a configuration of circuit breakers and cooperating equipment in two vertical stages so as to save floor space.
In the metalclad switchgear in FIG. 1 or 2, circuit breaker 12, 12a and 12b are located at a side of a door 36 or 36a and 36b so as to provide access to a single closed box 14 and 15. The closed box 14 is partitioned by a partition plate 16 into a circuit breaker compartment 18 and a cable compartment 20. A control line compartment 24 is formed above the circuit breaker compartment 18 through a partition wall 22 to protect a low-voltage control line (not shown) for controlling the circuit breaker 12 from a high-voltage section in the metalclad switchgear. A partition wall 28 is formed below the cable compartment 20 to form a bus compartment 26. The bus compartment 26 serves to shield a bus (not shown) arranged therein and a bus support conductor 27 for carrying the bus. Main circuit disconnecting devices 30 are mounted on the partition plate 16 opposite to output terminals of the circuit breaker 12. A power source side terminal of one main circuit disconnecting device 30 is connected to the bus support member 27 and an output side terminal of the other main circuit disconnecting device 30 is connected to a load cable 34 through a connecting conductor 32. Only electrical connections for one of the three phases are illustrated. The door 36 which can be opened/closed is arranged in front of the circuit breaker compartment 18, and a door 35 which can be opened/closed is arranged in front of the control line compartment 24. A ceiling plate 40 is disposed at a ceiling section, and a detachable cover 42 is arranged behind the cable compartment 20. A floor plate 44 is mounted below the closed box 14. A guide plate 46 is mounted on the floor plate 44 to guide the circuit breaker 12 upon insertion/removal thereof with respect to the closed box 14.
FIG. 2 shows a metalclad switchgear wherein circuit breakers and their cooperating equipment are housed in two stages in a single closed box 15. The metalclad switchgear of FIG. 2 is substantially the same as the structure obtained by vertically stacking two metalclad switchgears of FIG. 1 except that control line compartments 24a and 24b are arranged in front of circuit breaker compartments 18a and 18b to decrease the height of the closed box 15 in consideration of operability of a circuit breaker 12b. The circuit breaker compartments 18a and 18b and cable compartments 20a and 20b which are respectively partitioned by partition plates 16a and 16b are formed in the interior of the single closed box 15 which houses the entire structure of the metalclad switchgears of FIG. 2. The control line compartments 24a and 24b are formed on sides of the surface portions of the front portions of the circuit breaker compartments 18a and 18b at positions which do not interrupt access to the circuit breakers 12a and 12b. The control line compartments 24a and 24b are partitioned by partition plates. Bus compartments 26a and 26b are formed by partition walls 22a and 22b in the cable compartments 20a and 20b, and bus support conductors 27a and 27b are shielded by partition walls 22a and 22b, respectively. Main circuit disconnecting devices 30a and 30b are mounted on the partition plates 16a and 16b opposite to the terminals of the circuit breakers 12a and 12b. The power source side terminals of the main circuit disconnecting devices 30a and 30b are connected to bus support conductors 27a and 27b, respectively. The output side terminals of the devices 30a and 30b are connected to load cables 34a and 34b through connecting conductors 32a and 32b respectively.
Doors 36a and 36b which can be opened/closed are mounted at the front portions of the control line compartments 24a and 24b, a ceiling plate 40a is mounted on a ceiling section, and detachable covers 42a and 42b are mounted in the rear portions of the cable compartments 20a and 20b, respectively. Furthermore, a floor plate 44a is mounted in the lower portion of the closed box 15, and a floor plate 44b is mounted in the intermediate portion. Guide plates 46a and 46b are mounted on the floor plates 44a and 44b to guide the circuit breakers 12a and 12b upon insertion/removal thereof with respect to the box 15.
As can be apparent from the structures of FIGS. 1 and 2, even if the circuit breakers of identical ratings are used, the metalclad switchgears of FIGS. 1 and 2 are entirely different from each other. Therefore, circuit design and fabrication of the switchgear of FIG. 1 are entirely different from those of FIG. 2. In particular, when the type and model of cooperating equipment for the circuit breakers in the switchgears vary in every manufacturing process (the variation often depends on customer requirements), design cannot be started until the specification details of cooperating equipment are determined although the identical circuit breakers are used. As a result, the actual manufacturing time during the entire period from the placement of an order to the delivery of the metalclad switchgear is substantially short, resulting in inconvenience. The types and numbers of jigs and tools required for manufacturing metalclad switchgears of different shapes and dimensions are increased, and the management thereof becomes cumbersome. Furthermore, when a circuit breaker has high ratings, the metalclad switchgear becomes bulky, and transportation and installation as well as manufacture require greater skills.
When a failure occurs in a metalclad switchgear and even if a failure occurs in one of the spaces i.e, compartments partitioned by the partition plates in the metalclad switchgear, the closed box must be replaced since it cannot be divided into parts. Therefore, the time from power failure until recovery is prolonged, and the power supply of the adjacent metalclad switchgear is interfered with.